Centrifugal governor



BGE]

EGE

Mrch 16 1926.

J. ROMEYN CENTRIFUGAL GOVERNOR 2 sheets-sheet' a Filed Jan. 9. 1923 Patented Mar. 16, 1926.

JEAN ROMEYN, OF ST. GILLES, NEAR BRUSSELS, BELGIUM,

CENTRIFUGAL GOVERNOR.

Application led January 9, 1923. Serial No. 611,6671.v

T all whom t may concern.' Y

Be it known that I, JEAN ROMEYN, a subject of the Queen of Netherlands, and resident of St. Gilles, near Brussels, Belgium, have invented certain new and useful Improvements in Centrifugal Governors; and I do hereby declare the following to be a full, clear,'and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, and to letters or gures of reference marked therein, which form a part of this specification.

The present invention relates to centrifugal governors of the kind in which the action exerted by a spring or by springs is opposed to the centrifugal forces, `an'd especially lto those which can be adapted to operate at different speeds by altering, while running, ythe tension of the spring or springs.

According to the invention, the springs are arranged parallel to the governor shaft or nearly so, and have oneV of their ends attached to a part to which a sliding displacement along the shaft can be imparted, in order to change the speed at which the governor works; the other end of each spring 'is attached to a lever which is pivoted on a knife edge, and at such a point that the elementary variation of the length of the spring corresponding to a given elementary radial displacement of the centrifugal masses increases continuously when the governor opens; the lever just referred to vtransmits the action of the spring' to one Vof the centrifugal masses which are supported by separate levers.

In order that the advantages ofthe present invention may be better understood, it will be advisable to present in a suitable form the general theory of operation of governors of this class.

Figures l, 2 and 3 of the accompanying drawings refer to the general theory, whereas Figs. 4, 5, 6 and 7, which will be explained later on, are .applicable to the subject Lof the present invention.v

Let us consider a spring governor, the

shaft of which will be supposed to bevveri ugal mass is pivoted on a horizontal pivot and moves ina radial plane.

The lever which kbears each centrifugal mass is subjected to several moments,'which can be reduced when neglecting friction, to the following four:

(l) A moment created by the centrifugal force of the mass;

(2) A momentv produced by the centrifugal forces acting upon each portion of the governor connected to the consideredy mass;

(3) A moment created by the tension of the springs, acting directly or not, upon the centrifugal mass;

(4) A moment produced by gravity acting upon each portion connected to the mass.

For each position of the mass, the four moments hereabove can be replaced by four horizontall and radial forces applied to the centre of gravity of the mass, and having the same effect.

We will designate the centrifugal force of the mass by C, the forcecorresponding to the centrifugal forces of all parts connected therewith by c, the force corres nding to the action of the spr-ing by and the force produced by the action of gravity on each portion connected to the' mass by W.

- These forces will be considered as positive when acting outwards.

We will further designate' by r the minimum distance from the centre of gravity of the mass to the centre-line of the shaft, by R the same distance, when at a maximum, by wo the minimum angular speed and by w1 the maximum angular speed between which the governor is designed to work.

Let us consider, with a constant angular speed equal to wo the different positions of the mass, between the distances corresponding to r and R. When tracing (Fig. l)

la diagram of the centrifugal force C, we y will have of course a straight line'AB the `prolongation of which goes through O.

Supposing We add to 1the ordinates of the diagram AB the corresponding values of 0, We will have a curve AB. The force c is generally small as compared With C and its variation is not far from linear. Therefore, We can replace the curveV AB by the straight line ABO Without any appreciable error.

upposing now the governor rotates at a new constant angular speed fw2 all ordinates of the diagram above referred to will be multiplied with the same ratio l l wz 2 wo) so that the new diagram of C-l-c Will be illustrated .by yanother line (for instance AB) cutting the abscissa at the same point O. l v

lVh'en rplotting in the diagram of Fig. l, the curve of (Sel-W) We Will obtain a curve such as A C having its initial point superposed on the initial Lpoint ofthe curve representingC-l-c and its inal point higher than the final point of the curve C+C: the reason :for this is that Vthe state of equilibrium is attained at ythe speed wo corresponding tothe diagram AB when the dis tance from the centre of gravity of the mass to the shaft centre line is 1r, While equilibrium is attained at the speed fw1 w0 When the said distance is equal to R..

Furthermore We must have Once morey We Will make an error 0f minor importance if We replace the curve AC by the straight line AC, cutting QE at the point F. v

Suppose vthe tension of the spring or j springs to be altered in orderV to render the equilibrium speed corresponding to the minimum distance r. equalto wg a vnew diagram of -f (S-l-Ylllsuch as AC, will be i obtained (supposed again to be straight) having its initial point superposed on'the initial point of the diagram A. 13 (corresponding to the constantspeed wz). if kw3 is the maximum angular speed of equilibrium for the governor thus altered,

- is again true.

The condition for obtaining the same coetlicient of irregularity as before When reducing the speed as considered here above7 will read It Will be now shown'that this condition is fullled only when .the point F falls on the pointF. i

Therefore a straight line FGH may be drawn parallel to OAB and then EVD FD.

'If the variable force which the spring exerts upon the movable part to whichl it is attached be replaced by a constant orc'e f and for each position of the mass the horizontal force F having the same effect as the moment developed by f be calculated, a

diagram such as JK Fig. 2 Will be obtained for eF the ordinates of Which are proportional to the chosen force Consequently if the curve JK vbe replaced by the straight line JKL (which generally can be done Without anyappreciable error)l it can be said that the position of the point L is constant Whatever the force f may be, and depends onlyfupon the dimensions of the connecting parts through which the action of the force f is transmitted to the mass.

`Let'us now trace (F ig. 3) the actual diagram MN kof vthe Jforce -S corresponding to the spring and also the diagram AC of (S-l-VV) corresponding to the combined action of spring and gravity. These two diagrams maybe supposedas an approximation -to be straight lines. On drawing through ythe point P (whether or not it falls between the Vordinates corresponding to fr and R) the straight line PL (the point L being the samev as in Fig. 2), the diagramy JKL can be considered as representand corresponding to a constant torce j of convenient value acting upon the mechanism instead of the spring. Consequently the ordinates between the lines JK and MN co1n respond likewise to the action ot the difierent positive and negative forces which have to be added to the constant force f in order to obtain the diii'erent actual forces of the spring in the various positions considered. It the governor is so designed that the speed can be altered Without varying the coeliicient of irregularity, by altering the tension of the spring or springs, for a second Working speed a diagram oij (S-l-VV) such as FAC will be obtained (Fig. 3)

' onstrated above.

tl (l lll5 llll

ing a force applied horizontally tothe mass As the4 action of gravity .alwaysremains the same, the dia am of 8, will go through the points and-N the distances M A and NC being equal to MA and NC respectively. Consequently the points P and P will fall on the same ordinate.

Whe-n drawing the straight line PL, the diagram JK will represent the action upon the mass of a constant force equal to the actual force of the spring for the posit1on corresponding to the point P and act- 1ng upon the mechanism instead of the spring.

If'we consider only the case of helical springs the number of coils of `which is constant, the variation of the force, when passing from a given position of the `movable spring end corresponding to the points P and P to any other position, is independent of the actual force of the spring in the initial position. Therefore the distances MJ and NK must be respectively equal to MJ and NK.

4 As the ordinates between the diagram MN and AC are equal to the corresponding ordinates between MN and AC and furthermore as the ordinates between AC', and-JK are equal to those between AC and J'K' multipiieaby lthe condition linsty above expressed cannot be fulfilled unless the point L falls on the point F. Hence the following two rules may be enunciated:

\ When" it isproposedto obtain a constant degree of irregularity at various speeds with a'spring governor byaltering the tension of the spring 4or springs without changing the stiffness of thespring or springs, nor the relation between the elementary variation of the length of the spring or springs and the elementary displacement ofthe masses in the different positions:

(l) The-governor must be so designed, that at a given working speed, but taking into account the degree of irregularity to be obtained,` the action of all centrifugal forces can be balanced by a constant force acting in place of each spring. l

(2) The stiness of the spring or springs must .be such thatkthe action of gravity applied to all movable parts is exactly balanced by the variable force which must be added to Vor subtractedrfrom the-constant `force just referred to in order to obtain the actual force of the spring or springs.

From these, a vthird Vrule may be deduced: As the centrifugal force carries out a motive work when the ydistance between the mass and the shaft increases, this work is finally transmitted to the spring. Consequently its length must increase, and also the force it develops. Thus lthe diagram of S must be more inclined with respect to the abscissa,'than the diagram A C whlch corresponds to the 'actionof a constantforce, according Ato the first rule. A' f ,i ,ap

' As the forces represented by thejordinates between the diagram AC of (S-I-VV) .and the diagram MN ofl -S mustsbe balanced by the action of gravity (second rule) ythe diagram of W must be inclined-as shown in Fig. 3 by the line ST, and the diagram of W as shown by STY.

VVhence the third rule:

The governor must be so designed that the action of gravity is `more opposedA (or lessfavorable) to the action ofthe centrifugal force when the radius is at a minimum than when at its maximum.

In order that the invention may be better understood, F igs. t', 5, 6 and 7 may be referred to which show by way of example a particular form of construction; and it isshown how the three rules above mentioned are applied thereto andl how several further `motionto lever g supported by the rod 7L pivoted at i on a fixed part, does not rotate with the shaft; it is connected with the levers "c by means of square blocks y', each of which is provided with a pin lc engaged in the eye of the adjacent lever c. Theblocks j slide in the circular groove Zy of the sleeve F. The weights are round bodies and are free to rotate on their pins m.

The springs n are nearly parallel to the shaft. One of their ends .is attached to thc sleeve 0, which is rotated by the shaft by means of a key p', but can be displaced. up

and down by means of the collar g, the' lever fr, the rod s, the screw t and thehandwheel u. f

Each spring acts upon a bell crank lever o pivoted at jw on a knife edge and bearing `against' the corresponding weight atits l'lattened end y Y The pivot point'l is `situated below -th weight and so the third rulel above referred to is observed i. e., the action ofV gravity is opposed to a maximum degree to the action of centrifugal force.

The point at which the spring isvconnected with the lever o is situated below the fulcrum point e0 ofthe lever and nearer the shaft. It is easy to choose its position so that the distance g/ remains nearly proportional to the centrifugal force when the governor opens, and in this way the first rule can be observed, with a suiliciently close approximation. v f

-lllO the weights roll against the ends 0J of the levers c. Moreover, as `the sleeve vy does not rotate with the shaft, the vertical component ofthe friction developed between both parts is equal to the total friction multiplied by the Vratio of the verticaly speed of the o sleeve to the total relative speed of the survertical.

facesin contact. The sleeve thus acts just 1n the same manner as an oil brake: its ac- Vtion is very slight when the vertical movement of the sleeve is very slow.

Furthermore, supposing the tension of tl'ie springs or the centrifugalV forces 'to be unequal, the only result thereof is that there are additional reactions between the shaft and the sleeve at both ends thereof, but it has just been explained that the friction rcsulting from such pressures Vcannot lessen the sensitiveness of the-governor.

No special care is taken to avoid .friction at the pivot points m, cl, and le, but ythe forces acting upon these pivot ypins are not important as compared with the centrifugal force: they .are due to gravity only and to a small component of the force exerted byV the lever c upon the weight t, in the positions in which the surfaceof Contactl is not Ifthe tension of the different springs-is not equal, there would be an additional friction at the points m, d, and 70, owing to the balancing force which would be transmitted from one mass to the other. Therefore, the mechanism can be improved by mounting on the sleeve o a lever e, as shown in Fig. 5.

The governor described presents a further distinct advantage: kIn many cases the shaft upon which a governor is mounted is so designed asto-fullil other purposes (for instance to transmit the movement from the crank-shaft of an engine to the cam-shaft) and as a consequence thereof the said shaft cannotbe dismantledY easily as a whole.

VWhen the governor described is mounted upon such a shaft, the springs can be taken away and replaced without any difficulty, which is not the case in the governors in which the spring or springs is or are mounted around the shaft.

Of course, it is also possible to observe the three rules above referred to when attaching directly the spring to the lever c, as shown in Fig. 6, and in thiscase the weight can be solid with the said lever.Vv But for Vthe sake of sensitiveness, it is then necessary to employ a knife edge d at the` point d.

In this latter design, Aowing to the considerable weight-of part b, c, and to thelateral clearance, which cannot be dispensed with at the point d, the angular accelerations to which the governor shaft may be subjected willcause, in certain circumstances, a small sliding movement of the part b, c, along the edge of. the knife, which might injure the said edge, In the' case of Fig. 4, there can be no'sliding movement of the lever Q2, because the inertia applied to this light part will always be less than the lateral friction developed by the pressure on the knife edge. In the design ofl Fig. 6 it willbe necessary to prevent the said sliding movement at the edge of the knife, by allowing` forv a small sliding movement of the knife dritself in the holes of part c, in which itis fitted.

Obviously, the `number of weights is not limitedrfthere can'be, 4 or moreweights without departing from the scope `of the invention. l j f The weights can also be connected with the sleeve in the Amanner shown in Fig. 7, although this design is less satisfactory as regards friction; xinthis case the sleeve f -would rotate with the shaft, and be connected with the lever g by means of a sliding member. Finally the sliding parts j can be replaced by rollers.

I claimy as myinvention- 1. Inv a centrifugal governor, the combination, with a rotatable shaft, of a plurality of centrifugal weights; a carrier`V lever individual v.to each weight; a controlling sleeve movable along the shaft and connected with the levers; a set of helical springs, one for each weight, disposed approximately parallel with said shaft; a member freely adjustable on said shaft while the latter is rotating and with which one end of each spring is connected; and a set of bell-crank levers, one for Veach Weight and bearing thcreagainst at one end, each bell-crank lever being fulcrumed intermediate its ends on a knife-edge bearing andV connected at its other end to the other end of the associated spring.y f v 2. Ina centrifugal governor, the combination, with a rotatable shaft, of a plurality Vof weight-carrying levers; a centrifugal weight vindividual to each lever and having the `formV of a round body pivotally ysupported at its center thereon; a controlling sleeve movable'along the' shaft andv connected with said levers; a set of helical springs, one for veach weight, disposed approximately parallel' with said shaft; a 'member freely adjustable on' said shaft while the latter is rotating and to which one end of each spring Iis connected; and a 'set of bell-crank levers, one for each weight and bearing thereagainst at one end, each bell-crank lever being VVfulcrummed intermediateits ends ona knife-edge bearing and lll() connected at its other end to the other end of the associated. spring.

3. In a centrifugal governor', the combination with a rotatable shaft, of a plurality of centrifugal weights; a carrier lever individual to each weight; a controlling sleeve movable along the shaft and connected With the levers; a set of helical springs, one for each Weight, disposed approximately parallel with said shaft; a member freely adjustable on said shaft While the latter is rotating and with Which one end of each spring is connected; and a set of bell-crank levers, one for each Weight and bearing thercagainst at one end, each bell-crank lever being fulcrumed intermediate its ends on a knife-edge bearing and connected at its other end to the other end of the. associated spring; the last-named point of attachment of each bell-crank lever being arranged below the ulcrum point of that lever and closer to the shaft than said fulcrum point, and each Weight being arranged above the fulcrum of its carrier lever, such relative arrangement remaining constant for all speeds of rotation of the shaft.

In testimony whereof I affix my signature.

JEAN ROMEYN. 

